Recently, macromolecule compounds having a .pi.-conjugated system are appreciated as materials utilizing the electrolytic and optical function. In these macromolecule compounds having the .pi.-conjugated system, .pi. electrons in the system are directed in one dimension along with the principal chain of the macromolecule. Therefore, electrolytic anisotropy and optical anisotropy are shown between one direction along with the principal chain and the other direction perpendicular to said one direction.
It is necessary to orientate the principal chain of the macromolecule in a predetermined direction for utilizing the electrolytic anisotropy and optical anisotropy effectively. However, these macromolecules are stiff, insoluble and hard to melt, because the .pi. electrons are directed in one dimention along with the principal chain. Therefore, it is difficult to give a predetermined shape to the macromolecule and to orientate the principal chain in a predetermined direction.
As these conductive materials having the .pi.-conjugated system along with the principal chain, various compounds such as shown below are known. ##STR2##
However, because most of the known conductive macromolecules having the .pi.-conjugated system are insoluble to organic solvents etc. and hard to melt, an effective method for processing them has not been found. It is rather difficult to mold and give a predetermined shape to the known macromolecules. Therefore, only limited applications have been found for the macromolecules and the unique functions of them have not been utilized effectively.
To solve the above problems, it has been attempted to introduce a substitution group into the aromatic ring of polythiophene, poly-p-phenylene, polypyrrole or the like for improving the solubility of these compounds to the organic solvents.
Moreover, the above known macromolecules become only p-type conductor by oxidation.
Therefore, it is desired to develop materials having properties not shown in the prior conductive macromolecules by modifying the chemical structures of them. For example, it is desired to develop a .pi.-conjugated conductive macromolecules indicating n-type conductivity other than p-type conductivity which has already obtained by the prior conductive macromolecules. Such conductive macromolecules indicating n-type conductivity can be used for semiconductor devices.
On the other hand, it is easy to obtain a n-type conductor by reducing polypyridine shown above. However, polypyridine is soluble only to limited solvents such as formic acid or concentrated sulfuric acid and therefore its application is very limited. Moreover, the molecular weight of polypyridine is not large enough for preparing strong films made of polypyridine and therefore application of a polypyridine film is very limited.